Abstract: A means of reflecting and emitting electromagnetic energy in an appropriate wavelength band comprising an arrangement (10) of surfaces (11) which are reflective to energy in that wavelength band and energy emitters (12) having an emission of energy of such intensity that the combined reflection and emission of said surfaces match energy of a background in that wavelength band thereby camouflaging the surfaces. The said emitters (12) comprise strips of material which, upon energizing with an electric current, become heated and radiate energy. The means further comprises at least one radiometer (17) in association with a comparison means to provide an electrical signal which is a function of the difference between the combined reflection and emission and of the background, the electrical signal controlling the energization of the energy emitters (12).